de.kp.ames.web.core.json.JsonUtil.java Source code

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Here is the source code for de.kp.ames.web.core.json.JsonUtil.java

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package de.kp.ames.web.core.json;
/**
 * This Java module is part of the
 *  Application Developer Framework
 *
 *  Project: AMES-Web-Service
 *  Package: de.kp.ames.web.core.json
 *  Module: JsonUtil
 *  @author krusche@dr-kruscheundpartner.de
 *
 * Add your semantic annotations within the SemanticAssist tags and
 * mark them with a leading hashtag #:
 *
 * <SemanticAssist>
 *     #core #json #util #web
 * </SemanticAssist>
 *
 */

/**
 *   Copyright 2012 Dr. Krusche & Partner PartG
 *
 *   AMES-Web-Service is free software: you can redistribute it and/or 
 *   modify it under the terms of the GNU General Public License 
 *   as published by the Free Software Foundation, either version 3 of 
 *   the License, or (at your option) any later version.
 *
 *   AMES- Web-Service is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
 * 
 *  See the GNU General Public License for more details. 
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this software. If not, see <http://www.gnu.org/licenses/>.
 *
 */

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

public class JsonUtil {

    /**
     * A helper method to retrieve Array-based attribute 
     * values from the provided JSONObject
     * 
     * @param key
     * @param jObject
     * @return
     * @throws JSONException
     */
    public static ArrayList<String> getAttributeAsArray(String key, JSONObject jObject) throws JSONException {

        ArrayList<String> values = null;

        if (jObject.has(key)) {

            /* 
             * Retrieve json array from in more fault tolerant manner
             */
            JSONArray jArray = getJArray(key, jObject);
            if (jArray.length() > 0) {

                values = new ArrayList<String>();
                for (int i = 0; i < jArray.length(); i++) {
                    values.add(jArray.getString(i));
                }
            }

        }

        return values;

    }

    /**
     * A helper method to convert a JSON (String) array
     * into a String array
     *
     * @param jArray
     * @return
     * @throws JSONException
     */
    public static ArrayList<String> getStringArray(JSONArray jArray) throws JSONException {
        /*
         * Convert JSON array into String representation
         */
        ArrayList<String> array = new ArrayList<String>();

        for (int i = 0; i < jArray.length(); i++) {
            array.add(jArray.getString(i));
        }

        return array;

    }

    /**
     * @param key
     * @param jObject
     * @return
     */
    public static JSONArray getJArray(String key, JSONObject jObject) {

        JSONArray jArray = new JSONArray();

        if (!jObject.has(key))
            return jArray;

        try {

            /* 
             * First, try to retrieve the expected JSONArray
             * by regular means
             */
            return jObject.getJSONArray(key);

        } catch (JSONException e) {
            /* 
             * Second, try to reconstruct the respective 
             * JSONArray from a string
             */
            try {
                return new JSONArray(jObject.getString(key));

            } catch (JSONException ex) {
            }

        } finally {
            // do nothing
        }

        return jArray;

    }

    /**
     * This is a helper method to convert 
     * a collection of strings into a JSON
     * array
     * 
     * @param c
     * @return
     * @throws Exception
     */
    public static JSONArray getJArray(Collection<String> c) throws Exception {

        String[] cs = (String[]) c.toArray(new String[c.size()]);
        return new JSONArray(Arrays.asList(cs));

    }

}